Data networks typically include one or more network nodes that can serve as communication routers. Network performance may be characterized by tracking one or more performance indicators of the network nodes included in the network. For example, health status of a network node may be evaluated by issuing a periodic “heartbeat” signal originating within the network and subsequently monitoring whether or not the heartbeat signal has been received at the network node. Receipt of the heartbeat signal can be indicative that data packets can be transmitted and received at the network node. Evaluating one or more quantities derived from performance indicators may be useful in monitoring network performance.